Maintaining golf course grass is a science. A clean cut on each blade of grass is preferred because a ragged cut stunts growth and weakens the grass. When the grass is weakened it becomes prone to disease. Diseased grass is attacked by weeds. When weeds develop costly chemicals are needed to kill the weeds. In order to cut the grass cleanly, reel mower blades need to be sharpened frequently. Most prior art sharpening systems require removing the reels from the mower frame to perform the sharpening process. This removal and re-installation of the reel blades is costly in terms of labor costs as well as downtime for the expensive power lawnmower.
A brief summary of the prior art sharpeners follows below. Dieck et al. '581 claims to perform both the “true” grind of the reel tips and the “relief” grind of the trailing edge of each blade without the removal of the reel from the mower.
U.S. Pat. No. Re 28,200 (1974) to W. E. Witt et al. discloses a reel lawnmower sharpener, wherein a motorized grinder is mounted to the frame to sharpen the blades.
U.S. Pat. No. 4,148,158 (1979) to Hewitt discloses a lathe-type machine, which receives the frame of a reel mower, and mechanically grinds each blade.
U.S. Pat. No. 4,163,345 (1979) to Meili discloses a rotary lawnmower sharpener.
U.S. Pat. No. 4,192,103 (1980) to Sousek discloses a reel lawnmower grinder that has an automatic indexing device to advance the cutter reel blades into the grinder.
U.S. Pat. No. 4,485,591 (1984) to Bolin discloses a portable, ground mounted motorized grinder on a frame which can connect to the underside of a reel type mower.
U.S. Pat. No. 4,550,532 (1985) to Fletcher, Jr. et al. discloses a robotic grinder for grinding an elongated blank.
U.S. Pat. No. 4,746,330 (1988) to Johnson discloses a reel mower blade sharpener with a pulley system to rotate the blades in synch with the sharpener.
U.S. Pat. No. 5,012,617 (1991) to Winstanley discloses in FIG. 4 a reel mower blade assembly mounted on a dual purpose grinder for sharpening both the rotating blades and the fixed bottom blades.
U.S. Pat. No. 5,321,912 (1994) to Neary et al. discloses a tabletop spin grinder for a reel type mower, wherein the perfect cylindrical shape of the blade is assured.
U.S. Pat. No. 5,879,224 (1999) to Pilger discloses a tabletop grinder for a reel mower, with an automatic blade indexer.
U.S. Pat. No. 5,549,508 (1996) to Searle et al. discloses a tabletop grinder for a reel mower, with an indexer and a dampening mechanism to minimize grinding vibrations.
U.S. Pat. No. 5,725,415 (1998) to Bernhard discloses a portable grinder for the bed knife or bottom blade of a reel mower.
U.S. Pat. No. 6,010,394 (2000) to Dieck et al. discloses a tabletop reel grinder with sophisticated blade indexing to reduce manual adjustments after initial first blade setup.
U.K. Patent No. 2 170 740 A (1986) discloses a tabletop reel grinder with a single hydraulic actuator for the traverse means for the grinder and the blade rotator is provided.
U.S. Pat. No. 6,290,581 B1 (2001) to Dieck et al. is assigned to Foley-Belsaw Company. The invention features a tabletop grinder for a reel blade. Both the “true” grind and the “relief” grind steps and automatic indexing are provided. A mechanical sensor (FIG. 7, 42) senses the blade position which controls the vertical positioning of the grinding head.
Each reel has a front and a rear roller which need to be parallel and set to a proper height. All known methods are manual to align these rollers.
Height adjustments for a golf course are complex. Generally the deep rough is set at 1½ to 2 inches. The intermediate rough is set at 1 to ¼ inch. The fairway is set at ½ to 1 inch. The greens are set at 3/32– 3/16 inch. The tees are set from 3/16–½ inch. Height adjustments are set to 0.001 inch for precision.
The present invention is rolled under a power lawnmower which is usually lifted on a power lift. No removal of the cutting units is necessary. A laser or a mechanical probe, an encoder, and a cutter based system is operated by the machinist using an on-board computer controller. The rollers are aligned using the encoder. The reel blades are sharpened using a machining head with end cutter. The bed knife is sharpened using the machining head with back facing cutter. The height adjustment is measured by the laser scanner or encoder probe to the exacting requirements of each height setting. Additionally the reel cylinder axis is measured by the laser scanner or encoder probe.
The overall benefits to the golf course owner are a very precisely conditioned reel mower which reduces costs to maintain the grass. The precise conditioning is also achieved in less time, thus reducing maintenance costs for the golf course. The system offers benefits to any grass mowing maintenance operation.